Buggy code:
public InputId getInputId ( ) { } public boolean isFromExterns ( ) { } public int getLength ( ) { } public void setLength ( int length ) { } public int getLineno ( ) { } public int getCharno ( ) { } public int getSourceOffset ( ) { } public int getSourcePosition ( ) { } public void setLineno ( int lineno ) { } public void setCharno ( int charno ) { } public void setSourceEncodedPosition ( int sourcePosition ) { } public void setSourceEncodedPositionForTree ( int sourcePosition ) { } protected static int mergeLineCharNo ( int lineno , int charno ) { } protected static int extractLineno ( int lineCharNo ) { } protected static int extractCharno ( int lineCharNo ) { } public Iterable < Node > children ( ) { } public Iterable < Node > siblings ( ) { } private static final class SiblingNodeIterable implements Iterable < Node > , Iterator < Node > { private final Node start ; private Node current ; private boolean used ; SiblingNodeIterable ( Node start ) { } @ Override public Iterator < Node > iterator ( ) { } @ Override public boolean hasNext ( ) { } @ Override public Node next ( ) { } @ Override public void remove ( ) { } } Node . PropListItem getPropListHeadForTesting ( ) { } public Node getParent ( ) { } public Node getAncestor ( int level ) { } public Node . AncestorIterable getAncestors ( ) { } public static class AncestorIterable implements Iterable < Node > { private Node cur ; AncestorIterable ( Node cur ) { } @ Override public Iterator < Node > iterator ( ) { } } public boolean hasOneChild ( ) { } public boolean hasMoreThanOneChild ( ) { } public int getChildCount ( ) { } public boolean hasChild ( Node child ) { } @ VisibleForTesting public String checkTreeEquals ( Node actual ) { } @ VisibleForTesting public String checkTreeEqualsIncludingJsDoc ( Node actual ) { } Node . NodeMismatch checkTreeEqualsImpl ( Node node2 ) { } private Node . NodeMismatch checkTreeEqualsImpl ( Node node2 , boolean jsDoc ) { } public boolean isEquivalentTo ( Node node ) { } public boolean isEquivalentToShallow ( Node node ) { } public boolean isEquivalentToTyped ( Node node ) { } boolean isEquivalentTo ( Node node , boolean compareJsType , boolean recurse , boolean jsDoc ) { } public String getQualifiedName ( ) { } public boolean isQualifiedName ( ) { } public boolean matchesQualifiedName ( String name ) { } private boolean matchesQualifiedName ( String qname , int endIndex ) { } public boolean matchesQualifiedName ( Node n ) { } public boolean isUnscopedQualifiedName ( ) { } public boolean isValidAssignmentTarget ( ) { } public Node detachFromParent ( ) { } public Node removeFirstChild ( ) { } public Node removeChildren ( ) { } public void detachChildren ( ) { } public Node removeChildAfter ( Node prev ) { } public Node cloneNode ( ) { } public Node cloneTree ( ) { } public Node copyInformationFrom ( Node other ) { } public Node copyInformationFromForTree ( Node other ) { } public Node useSourceInfoFrom ( Node other ) { } public Node srcref ( Node other ) { } public Node useSourceInfoFromForTree ( Node other ) { } public Node srcrefTree ( Node other ) { } public Node useSourceInfoIfMissingFrom ( Node other ) { } public Node useSourceInfoIfMissingFromForTree ( Node other ) { } public JSType getJSType ( ) { } public void setJSType ( JSType jsType ) { } public Node . FileLevelJsDocBuilder getJsDocBuilderForNode ( ) { } public class FileLevelJsDocBuilder { public void append ( String fileLevelComment ) { } } public JSDocInfo getJSDocInfo ( ) { } public Node setJSDocInfo ( JSDocInfo info ) { } public JSTypeExpression getJSTypeExpression ( ) { <START_BUG> return ; <END_BUG> } public Node setJSTypeExpression ( JSTypeExpression jsTypeExpression ) { } public void setChangeTime ( int time ) { } public int getChangeTime ( ) { } public void setVarArgs ( boolean varArgs ) { } public boolean isVarArgs ( ) { } public void setOptionalArg ( boolean optionalArg ) { } public boolean isOptionalArg ( ) { } public void setIsSyntheticBlock ( boolean val ) { } public boolean isSyntheticBlock ( ) { } public void setDirectives ( Set < String > val ) { } @ SuppressWarnings ( "unchecked" ) public Set < String > getDirectives ( ) { } public void addSuppression ( String warning ) { } public void setIsAddedBlock ( boolean val ) { } public boolean isAddedBlock ( ) { } public void setStaticMember ( boolean isStatic ) { } public boolean isStaticMember ( ) { } public void setIsGeneratorFunction ( boolean isGenerator ) { } public boolean isGeneratorFunction ( ) { } public void setGeneratorMarker ( boolean isGeneratorMarker ) { } public boolean isGeneratorMarker ( ) { } public void setGeneratorSafe ( boolean isGeneratorSafe ) { } public boolean isGeneratorSafe ( ) { } public void setIsArrowFunction ( boolean isArrow ) { } public boolean isArrowFunction ( ) { } public void setYieldFor ( boolean isGenerator ) { } public boolean isYieldFor ( ) { } public static final int FLAG_GLOBAL_STATE_UNMODIFIED = 1 ; public static final int FLAG_THIS_UNMODIFIED = 2 ; public static final int FLAG_ARGUMENTS_UNMODIFIED = 4 ; public static final int FLAG_NO_THROWS = 8 ; public static final int FLAG_LOCAL_RESULTS = 16 ; public static final int SIDE_EFFECTS_FLAGS_MASK = 31 ; public static final int SIDE_EFFECTS_ALL = 0 ; public static final int NO_SIDE_EFFECTS = ( ( ( Node . FLAG_GLOBAL_STATE_UNMODIFIED ) | ( Node . FLAG_THIS_UNMODIFIED ) ) | ( Node . FLAG_ARGUMENTS_UNMODIFIED ) ) | ( Node . FLAG_NO_THROWS ) ; public void setSideEffectFlags ( int flags ) { } public void setSideEffectFlags ( Node . SideEffectFlags flags ) { } public int getSideEffectFlags ( ) { }

Fix:
return ( ( JSTypeExpression ) ( getProp ( Node . DECLARED_TYPE_EXPR ) ) ) ;